1. Field of the Invention
The present invention relates to a spatial light modulating apparatus for displaying a plurality of two-dimensional images obtained by seeing a target object from different visual point positions, thereby allowing a stereoscopic image to be seen. More particularly, the invention relates to a spatial light modulating apparatus having a structure such that a number of pixel light sources for displaying the 2-dimensional image and mirror devices for deflection are integrated.
2. Description of the Related Art
Hitherto, various studies and developments of a display apparatus by which a stereoscopic image can be seen and recognized have been made. A conventional stereoscopic display apparatus is of a double-eye type which is represented by a spectacle type. Different video images are shown to the right and left eyes, thereby obtaining a stereoscopic feeling by a vergence of two eyes or a parallax of two eyes. As an extension of the double-eye type, there is an apparatus using a lenticular lens of a multieye type. The principle for allowing a stereoscopic image to be seen in such an apparatus is similar to that of the double-eye type and a video image of about eight eyes is obtained. However, a stereoscopic image can be seen only at a predetermined position. In such a conventional apparatus, since no difference (motion parallax) occurs in the stereoscopic image to be observed even when the observer moves his head to the right and left, only an unnatural stereoscopic image can be seen.
A holographic stereogram can be mentioned as an apparatus which can solve the above drawbacks. According to the holographic stereogram, a two-dimensional video image including a parallax is recorded in a slit-shaped segment holograms which is elongated in the vertical direction and a number of segment holograms are arranged in the horizontal direction. Therefore, even when the observer moves his head to the right and left, a natural stereoscopic feeling can be obtained. In case of electrically displaying the holographic stereogram, however, it is necessary to calculate a phase distribution every time the display image changes, so that there is a problem such that a calculation load is large.
As an apparatus to solve such a problem, the applicant of the present invention has proposed "Stereoscopic Display Apparatus" of U.S. patent Ser. No. 08/125,660 (filed on Sep. 23, 1993). The stereoscopic display apparatus comprises as shown in FIG. 1: a display 400 for displaying a 2-dimensional image; a deflection diffusing section 410 for deflecting a light emitted from each pixel of the display 400 in the horizontal direction, thereby diffusing; and further, a lenticular lens 420 which functions as a directional enlarging section for enlarging the light in the vertical direction. When stereoscopically displaying, a preset observation range 440 is divided into stripe-shaped visual point regions A1 to An each of which is long in the vertical direction and different 2-dimensional images which are obtained by seeing an object from the visual point regions are prepared. The 2-dimensional images are time-divisionally displayed by the display 400 and the deflection diffusing section 410 is driven, thereby deflecting a bundle of light beams from the 2-dimensional image to a corresponding visual point region. In the case, therefore, where eyes 450-1 and 450-2 of the observer are positioned, for example, at visual point regions Ai and Ai+k, two 2-dimensional images which are differently seen are observed in the visual point regions and the stereoscopic feeling can be obtained. According to the stereoscopic display apparatus, a stereoscopic display which is equivalent to a holographic stereogram can be performed without calculating an enormous amount of phase distributions.
In order to realize the stereoscopic display apparatus of FIG. 1, a device in which modulating devices of the light intensity to display the pixels of the 2-dimensional image and devices for deflecting the lights from the pixels synchronously with the image display are two-dimensionally arranged is necessary. As such a device, for example, a device in which mirrors and light emitting devices are combined and 2-dimensionally arranged and the light whose intensity was modulated by the light emitting device is deflected by the mirror is considered. In the apparatus which has already been proposed, since a galvano mirror is used as a mirror, an area which is occupied by one pixel is large, so that the apparatus cannot be miniaturized. On the other hand, in the field of an optical computer or the like, studies of a device in which fine mirror devices are arranged in an array shape and which is known as a deformable mirror device (DMD) are being performed. In an LED or a semiconductor laser, a manufacturing method of a device in which the light emitting devices are arranged in an array shape is also being studied and a device in which a plurality of light emitting devices are arranged in an array shape has been manufactured. By combining such a DMD and a light emitting device, a small stereoscopic display apparatus can be realized.
In the case where the light which was intensity modulated by the light emitting device is angle modulated by the deformable mirror device, however, as shown in FIG. 2, it is necessary to install a light emitting device 510 at a high position over a mirror device 520 formed along a surface 540 of a circuit board 500. Therefore, a flat circuit board shape isn't obtained and it is difficult to integratedly manufacture the device in which the light emitting devices for light intensity modulation and the mirror devices for angle modulation are two-dimensionally arranged.